Photographic contact printing apparatus



Jan. 6, 1970 I .J, DASSONVILLE PHOTOGRAPHIC CONTACT PRINTING APPARATUS Filed ma 2, 1967 INVENTOR. v JACQUES DASSONVILLE United States Patent O Int. e1. (5031, 27/08 US. Cl. 355-90 24 Claims ABSTRACT OF THE DISCLOSURE A contact printing apparatus wherein a master strip is biased against a photosensitive strip during travel past a copying station located in a liquid bath. The means for biasing the strips against each other comprises a nozzle whose orifice discharges a stream of liquid against the master strip during travel past the copying station, such liquid being collected by a tank which accommodates the nozzle. The latter is formed with a channel which guides the strips during travel past the copying station. The means for conveying the strips comprises a drum which is in positive motion-transmitting engagement with the master strip downstream of the nozzle and a hood which discharges jets of compressed gas against the photosensitive strip to bias the latter against the master strip during travel with the drum.

BACKGROUND OF THE INVENTION The present invention relates to photographic contact copying apparatus. More particularly, the invention relates to improvements in apparatus for transferring images developed on exposed positive or negative master strips onto strips of photosensitive material while the strips are held in direct contact with each other and are immersed in a liquid bath.

In presently known contact copying apparatus, the master strip and the emulsion strip are introduced separately into a liquid bath and are led into contact with each other to advance past a copying window and to be finally collected on take-up spools outside of the bath. Eventual scratches in the master strip are filled with liquid so that such scratches are not reproduced on the photosensitive strip. A serious drawback of such conventional apparatus is that they depict all foreign matter which adheres to the master strip and that the application and maintenance of requisite pressure between the tWo strips presents a num ber of problems.

Accordingly, it is an important object of the present invention to provide a contact printing apparatus wherein the strips are pressed against each other in a novel and improved way.

Another object of the invention is to provide a novel pressing or biasing device for use in the improved contact printing apparatus.

A further object of the invention is to provide a novel conveying unit for use in the improved contact printing apparatus.

An additional object of the invention is to provide a contact printing apparatus which automatically removes impurities from the master strip.

A concomitant object of the invention is to provide a contact printing apparatus which can be readily converted for use with relatively wide or relatively narrow master strips.

Another object of the invention is to provide a contact printing apparatus which can be operated continuously or intermittently and which automatically compensates for shrinkage of the master strip.

SUMMARY OF THE INVENTION One feature of my invention resides in the provision of a contact copying apparatus for reproducing images developed on a master strip onto a photosensitive strip during travel of such strips past a copying station in a liquid bath. The apparatus comprises conveying means for advancing the strips past the copying station, and pressing or biasing means for directing against one of the strips a stream of liquid during travel past the copying station to thereby urge the one strip against the other strip.

The pressing means preferably comprises a hollow body which constitutes a nozzle and has an orifice disposed at the copying station, and means for supplying pressurized liquid into the nozzle so that such liquid forms a stream which issues from the orifice to bear against the one strip. The nozzle is further provided with a guide channel a. median portion of which communicates with the orifice and which guides the strips so that the strips advance upwardly toward an intermittently or continuously driven drum of the conveying means. The nozzle is further provided with a light-admitting portion which is in line with the orifice and admits light rays against such increments of the strips which are in registry with the orifice.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved copying apparatu itself, however both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of a specific embodiment with reference to the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING The single figure is a schematic vertical sectional view of a copying apparatus which embodies my invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing illustrates a photographic contact printing apparatus which can copy images developed on a positive or negative strip 2 (hereinafter called master strip) onto a photosensitive strip 1. The apparatus comprises a biasing or pressing device for pressing successive increments of the master strip 2 against successive increments of the photosensitive strip 1, such pressing device including a hollow body in the form of a nozzle 3 having an orifice 8 and serving to direct a stream of pressurized liquid 4 against the master strip 2. The nozzle 3 is immersed in a tank 5 wherein the liquid level is determined by one or more overflow pipes 6. The internal space of the nozzle 3 tapers, either gradually or stepwise, in a direction toward the orifice 8. The refraction index of the liquid 4 at least approximates that of the emulsion coat and of the base layer; this insures the establishment of an optically isotropic zone in the nozzle 3 to conceal eventual flaws in the master strip 2. The liquid 4 should not attack the base layer of the strip 1 and should in no way alter the sensitivity and/ or the chemical properties of the emulsion coat. Suitable liquids are those in the family of halogenated hydrocarbons, such as trichlorethylene, trichlorethane, perchlorethylene, carbon tetrachloride and corresponding bromine compounds.

The nozzle 3 is provided with a light-transmitting portion in the form of a window pane 7 which is located in line with the orifice 8 and serves to admit light rays from a suitable source (not shown). The bottom wall of the nozzle is connected with a supply conduit 9 which admits pressurized liquid, and the nozzle further comprises an aerating pipe 10 which extends to a level above the liquid in the tank 5. If the strips 1, 2 are advanced continuously, the orifice 8 will resemble a narrow horizontal slit with 3 a width in the range of a few millimeters. If the strips 1, 2 are fed intermittently, the cross-sectional area of the orifice 8 will equal that of a film frame on the master strip 2, it being assumed that the strip 2 is fed by increments corresponding to the width of a frame.

The orifice 8 merges into the median portion of an elongated guide channel 11 which extends substantially at right angles to the optical axis, i.e., it is normal to the direction of travel of light rays from the pane 7 to the orifice 8. The width of the guide channel 11 is such that it can accommodate the strips 1 and 2 with minimal clearance and the liquid stream issuing from the orifice S insures that the strips are held in face-to-face abutment with each other. The liquid which flows from the orifice 8 into the channel 11 presses the strip 2 against the strip 1 and bleeds through the channel 11 to enter the interior of the tank 5. The channel 11 is of arcuate shape and its concave side faces the window pane 7. This compensates for shrinkage of the master strip 2 which took place during development. Such arcuate shape of the channel 11 contributes to nearly complete elimination of slippage between the strips 1 and 2 during travel past the orifice 8.

The conveying or advancing means for the strips 1 and 2 comp-rises a toothed drum or sprocket 12 whose shaft is horizontal and is driven continuously or intermittently by a suitable motor or transmission (not shown). The sprocket 12 is disposed below a hollow cover or hood 13 having an inlet connected with a supply pipe 14 for compressed gas and at least one outlet 16 which directs a jet of compressed gas in a direction toward the top half of the sprocket 12. The outlet 16 resembles an arcuate slot and is provided in a semicylindrical wall 15 of the hood 13; this wall 15 defines with the peripheral surface of the sprocket an arcuate passage for the strips. The longitudinal direction of the slot 16 is normal to the axis of the sprocket 12. The jet of compressed gas issuing from the slot or outlet 16 biases the photosensitive strip 1 against the master strip 2 while such strips travel with the sprocket 12. The master strip 2 has shrunk during treatment in a developer, and this strip 2 is placed in direct contact with the top half of the sprocket 12. The photosensitive strip 1 overlies the strip 2 along the upper half of the sprocket. A certain amount of slippage will take place between such portions of the strips 1, 2 which travel along the upper half of the sprocket 12, and the extent of such slippage is controlled by the pressure or volume of gases which issue from the plenum chamber in the hood 13. Thus, the gases issuing from the hood 13 serve as a means to produce a braking action upon the photosensitive strip 1 and to regulate slippage between the strips 1 and 2. Such regulation is effected without resorting to any mechanical means which could damage the strip 1.

When the master strip 2 is constituted by a 16 mm. film, a single arcuate slot 16 will suffice to control slippage. If the width of the strips 1 and 2 exceeds 16 mm., the wall 15 of the hood 13 may be provided with two or more parallel slots 16. It is also possible to provide one or more straight slots which extend in parallelism with the horizontal axis of the sprocket 12. Furthermore, the slot or slots 16 may be replaced by rounded or polygonal apertures or perforations in the wall 15. All that counts is to provide the wall 15 with one or more outlets in such distribution and with such combined cross-sectional area which insures uniform advance of strips 1 and 2 past the copying station (orifice 8).

The operation is as follows:

In order to copy the images on the strip 2 onto the strip 1, the leading ends of the strips 1 and 2 are threaded through the channel 11 from below before the tank is filled with liquid 4 up to the top end of the overflow pipe 6. The operators will form loops in each of the strips 1 and 2 in the region between the respective supply spools (not shown) and the lower end of the channel 11. The loop formed by the strip 2 is greater than the loop formed by the strip 1. In order to facilitate introduction of strips 1 and 2 into the channel 11, the front portion 17 of the nozzle 3 which bounds one side of the guide channel 11 is preferably removable from or displaceable with reference to the remainder of the nozzle. It is also preferred to mount the hood 13 in such a way that it can be readily lifted off the sprocket or drum 12 in order to facilitate placing of strips 1 and 2 over the top half of the sprocket. In the next step, the operator admits pressurized liquid 4 into the supply conduit 9 to fill the interior of the nozzle 3 and to fill the tank 5 to the level shown in the drawing. The apparatus is then ready to start with the copying operation. The intensity of light coming from the source located to the right of the windowpane 7 is adjusted in advance.

The strips 1 and 2 dip into the liquid in the tank 5 and are coated with thin films of liquid prior to entering the lower end of the guide channel 11. Such liquid films serve as a lubricant between the concave surface bounding the left-hand side of the channel 11 and the left-hand side or face of the photosensitive strip 1 (i.e., that side or face which is turned away from the master strip 2). The liquid films between the strips 1 and 2 also perform a desirable lubricating function, not only during travel through the guide channel 11 but also during advance along the upper half of the sprocket 12. The stream of pressurized liquid which flows through the orifice 8 and along the right-hand side or face of the strip 2 rinses away any solid impurities which might adhere to the strip 2 to thus prevent the formation of irregularities in the copied image. The liquid which overflows into the pipe 6 can be pumped back into the supply conduit 9 so that it is continuously recirculated through the nozzle 3 and tank 5. The pump which forces liquid into the supply conduit 9 is not shown in the drawing.

The strips 1 and 2 are separated from each other in the region downstream of the sprocket 12 and are dried during passage between the gas-discharging nozzles 18 of a suitable drier. The nozzles 18 are disposed in pairs at both sides of each strip and causes evaporation of moisture from the strips.

When the trailing ends of the strips 1 and 2 have advanced beyond the orifice -8, the operator arrests the aforementioned circulating pump and closes a suitable valve in the supply pipe 14. Liquid is thereupon drained from the tank 5 and from the nozzle 3 prior to introduction of fresh strips.

The contact copying apparatus of my invention can be used in connection with many types of master strips. The nozzle 3 is preferably detachable from the tank 5 so that it can be replaced with a different nozzle, and the same holds true for the advancing or conveying unit 12, 13. Such substitution of nozzles and advancing means will take place when the operator wishes to use the apparatus for copying from a wider or narrower master strip.

Another important advantage of my copying apparatus is that it can be operated at a speed which exceeds the speed of presently known contact copying apparatus, that it protects the strips against scratching and other damage, and that it does not reproduce flaws on the surface of the master strip. Also, the apparatus reduces slippage between the strips during travel past the copying station (orifice 8) to insure the production of highly satisfactory copies.

Without further analysis, the foregoing will so fully reveal the gist of 'the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.

1. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive strip during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; and pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip.

2. Apparatus as defined in claim 1, wherein said pressing means comprises a hollow body having an orifice disposed at said copying station and means for supplying pressurized liquid into said body so that such liquid forms a stream issuing from said orifice to bear against said one strip.

3. Apparatus as defined in claim 2, wherein said hollow body constitutes a nozzle having a light-admitting portion disposed in line with said orifice so that light admitted through said portion can impinge upon such increments of strips which register with said orifice.

4. Apparatus as defined in claim 3, wherein said lightadmitting portion comprises a transparent windowpane.

5. Apparatus as defined in claim 3, wherein said nozzle is provided with an internal space which tapers in a direction toward said orifice.

6. Apparatus as defined in claim 3, wherein said nozzle is further provided with an elongated channel extending substantially at right angles to the direction of light travel between said light-transmitting portion and said orifice, said channel being in communication with said orifice and being arranged to guide the strips past said copying station.

7. Apparatus as defined in claim 6, wherein said channel is of arcuate shape and has a concave side facing said light-admitting portion.

8. Apparatus as defined in claim 3, wherein said conveying means is arranged to advance the strips continuously and wherein said orifice is constituted by a slit extending substantially at right angles to the direction of travel of strips past said copying station.

9. Apparatus as defined in claim 3 for reproduction of images formed by a succession of frames on the master strip, wherein said orifice has a cross-sectional area corresponding to that of a frame on the master strip and wherein said conveying means is arranged to advance the strips intermittently so as to place successive frames of the master strip into registry with said orifice.

10. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive strip during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; and pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip, said pressing means comprising a hollow body constituting a nozzle having an orifice disposed at said copying station and means for supplying pressurized liquid into said nozzle so that such liquid forms a stream issuing from said orifice to bear against said one strip, said nozzle having a light-admitting portion disposed in line with said orifice so that light admitted through said portion can impinge upon such increments of strips which register with said orifice, said nozzle further having an elongated channel extending substantially at right angles to the direction of light travel between said light-admitting portion and said orifice and said channel being in communication with said orifice and being arranged to guide the strips past said copying station, said nozzle also comprising a portion bounding one side of said channel opposite said orifice and being movable with reference to the remainder of the nozzle.

11. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive strip during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; and pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip, said pressing means comprising a hollow body constituting a nozzle having an orifice disposed at said copying station and means for supplying pressurized liquid into said nozzle so that such liquid forms a stream issuing from said orifice to bear against said one strip, said nozzle further having a lightadmitting portion disposed in line with said orifice so that light admitted through said portion can impinge upon such increments of strips which register with said orifice, said nozzle also having a substantially vertical channel extending substantially at right angles to the direction of travel of light between said light-admitting portion and said orifice and including a median portion in communication with said orifice, said channel being arranged to guide the strips during advance past said copying station and said conveying means being arranged to draw the strips upwardly through said channel.

12. Apparatus as defined in claim 11, wherein the master strip is arranged to advance in front of said orifice so that the liquid stream impinges against the master strip and biases the latter against the photosensitive strip during travel past said copying station, the strips being arranged to form loops upstream of the lower end of said channel and the loop formed by the master strip being greater than the loop formed by the photosensitive strip.

13. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive strip during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip, said pressing means comprising a hollow body constituting a nozzle having an orifice disposed at said copying station and means for supplying pressurized liquid into said nozzle so that such liquid forms a stream issuing from said orifice to bear against said one strip, said nozzle further having a lightadmitting portion disposed in line with said orifice so that light admitted through said portion can impinge upon such increments of strips which register with said orifice; and a tank receiving said nozzle and arranged to collect liquid issuing from said orifice.

14. Apparatus as defined in claim 11, further comprising at least one overflow pipe arranged todetermine the upper level of liquid in said tank.

15. Apparatus as defined in claim 13, wherein said nozzle further comprises an aerating pipe extending upwardly beyond the liquid level in said tank.

16. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive strip during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; and pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip, the liquid of said stream having a refraction index which at least approximates the refraction index of the light-sensitive emulsion and of the support layer.

17. Apparatus as defined in claim 16, wherein the refraction index of the liquid corresponds to that of halogenated hydrocarbons.

18. Apparatus as defined in claim 1, wherein said conveying means comprises a rotary drum and a hood overlying a portion of the peripheral suiface of said drum and defining with the latter a passage for the strips downstream of said pressing means, said hood defining a plenum chamber for a compressed gas and having at least one outlet arranged to discharge such gas against one of the strips in said passage, the other strip being in direct motion-receiving contact with said portion of the drum.

.19. Apparatus as defined in claim 18, wherein said outlet is arranged to discharge gas against the photosensitive strip to press the latter against the master strip.

20. Apparatus as defined in claim 18, wherein said hood has a semicyclindrical wall which overlies said portion of the peripheral surface and wherein said outlet is provided in said semicylindrical wall.

21. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive strip during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip; and drying means provided downstream of said conveying means and said pressing means for drying each side of each of said strips.

22. Apparatus as defined in claim 21, wherein said drying means comprises nozzles arranged to direct a gas against the sides of the strips to evaporate the liquid which continues to adhere to such strips.

23. Contact copying apparatus for reproduction of images developed on a master strip onto a photosensitive stri-p during travel of strips past a copying station in a liquid bath, comprising conveying means for advancing the strips past said copying station; pressing means for directing against one of the strips a stream of liquid during travel past said copying station to thereby bias the one strip against the other strip; and a liquid-collecting tank accommodating said pressing means, said pressing means being removably received in said tank and said conveying means being replaceable together with said pressing means for treatment of different types of strips.

24. Apparatus as defined in claim 2, further comprising light-admitting means disposed in line with said orifice so that light admitted thereby can impinge upon such increments of strips which register with said orifice.

References Cited UNITED STATES PATENTS 3,061,159 10/1962 Jacobsen 226-97 X 3,143,267 8/1964 Maxey 226--95 3,161,120 12/1964 Timares et al 355-90 NORTON ANSHER, Primary Examiner R. A. WINTERCORN, Assistant Examiner US. Cl. X.R. 

